
aass /' ^ ^ ^ 



Book M JS 



ACROSS PAPAGUERIA. 



BY 

D. T. MACDOUGAL. 



reprinted from 

Bulletin of the American Geographical Socikiv, 

Vol. "^, December, 1908. 



i' i 



Ah 

Ml 



\' 



ACROSS PAPAGUERIA. 



BY 



D. T. MACDOUGAL. 



The Pacific coastal desert of North America extends from the 
region of the isthmus of Tehuantepec northward to inckide the pen- 
insula of Baja California and a part of Upper California. To the 
eastward one broad arm spreads out from the shores of the Gulf of 
California to include nearly all of Sonora, the southern and western 
part of Arizona and the southern part of Nevada, in which regions 
it joins the higher bolsons, mesas and basins of Chihuahua, New 
Mexico, Utah, Nevada and California. The entire region is one of 
great aridity, and probably no part of it under 4,000 feet in elevation 
receives more than 12 inches of rainfall annually; the ridges and 
peaks which rise above this level may have three times as much, by 
the condensing action of their summits. On the other hand, the 
great area lying to leeward pf the main peninsular ridge of Baja 
California and its northward continuation in California, are so situ- 
ated that the annual precipitation is often as low as 2j^ inches per 
year, while many localities receive no rainfall over periods as long 
as eighteen months, as noted by Palmer with regard to the Raza 
islands in the Gulf of California. 

No adequate natural history survey has yet been made of any 
portion of this region. The Boundary Survey Commission traversed 
the northern part in demarking the southern line of Arizona, the 
most arbitrary and meaningless political boundary in America, and 
made collections in the immediate vicinity of the line, but the nature 
of the work did not permit any attempt at studying the general rela- 
tions of the life of the region, although much detailed information 
was procured as to the composition of the fauna and flora. 



2 Across Papagueria. 

In the preparation of a resume of "The Botanical Features of 
North American Deserts" (PubHcation No. 99, Carnegie Instituti6n 
of Washington) it became apparent that systematic information on 
the general features of this region was very meagre, and an expedi- 
tion from the Desert Laboratory was planned which would traverse 
a route from Tucson to the Gulf. 

Tucson occupies a position on the eastern part of the great flattish 
ridge which slopes from elevations of three to four thousand feet in 
southeastern Arizona, westward to the delta of the Colorado River 
and the upper part of the Gulf of California. A score of mountain 
ranges, including the Whetstones, Santa Ritas, Santa Catalinas, 




Fig. I. — PORTION of papago village of querobabi. 

Tortolas, Tortolitas, Sierritas, Tucsons, Carobabis, Baboquiviris, 
Ouijotoas, Ajos, Growlers, Rincons, Dragoons, Mohawks, Gilas, 
Tules, Lechuguillas, Maricopas, Ciprianos, San Franciscos and San 
Rosarios, run transversely across the ridge with crests that rise to 
over 9,000 feet in some instances, the intervening valleys being for 
the most part broad, flattish troughs, with undeveloped drainage, 
opening to the northward into the Gila River and to the southward 
to the Altar and Sonoyta rivers in Sonora. 

The greater portion of this ridge has been occupied by the Papago 
Indians, since they became differentiated from the Piman stock, per- 



Across Papagiieria. 3 

haps ten or tv;elve centuries ago, this tribe being first encountered 
by the Spanish of Coronado's expedition in the middle of the i6th 
century. The region became known as Papagueria and was trav- 
ersed in many directions by zealous padres establishing missions 
and visitacioncs, one of which, the famous San Xavier, survives to 
this day. The Indian still occupies the country as a whole, very 
much as he did at the advent of the Castilian, and his relations to the 
climate and the desert conditions, as revealed by various anthro- 
pological investigations, are as interesting, biologically, as anything 
to be encountered by the naturalist. 

The expedition from the Desert Laboratory included Dr. W. T. 
Hornaday of the New York Zoological Park, Hon. J. M. Phillips of 
Pittsburg, Mr. Godfrey Sykes of the Desert Laboratory and the 
writer. Modern Tucson occupies the site of a frontier settlement) 
of Papagueria, the mountains within sight across the plains to the 
northward and eastward being anciently held by hostile tribes. The 
crest of the high black hill, Tumamoc, on the west side of the Santa 
Cruz River, is occupied by the remains of a village, the double and 
triple walls surrounding it on the precipitous slopes giving it secure 
protection. These walls in part accentuate the serrated effect of 
some of the profiles and doubtless helped to suggest its Papago name, 
which means "the horned toad hill." 

We were to follow the main trail from northeastern Papagueria 
to the salt beds on the shores of the Gulf of California near Adair 
Bay. A pilgrimage to these deposits became a matter of great 
economic and ceremonial importance in comparatively recent times, 
and salt brought from them is still occasionally offered for trade at 
outlying ranches. In addition to this historical interest, the general 
features of the fauna and flora promised evidence upon the major 
problems of habit and distribution of desert forms. Some of these 
reach their limit of occurrence on the slopes of the Santa Catalinas 
near Tucson and range southward and westward in Sonora between 
the mountains and the Gulf in such manner that the trip would make 
a complete section of their ranges. 

The route followed the main height of land at elevations of 2,000 
to 2,800 feet for a distance of 125 miles almost due west from Tucson 
until the northern end of the Ajo mountains was reached, when a 
sharp turn to the southward was made which soon took us out of the 
Gila drainage to that of the Sonoyta. This stream was first encount- 
ered south of the International Boundary near Monument 167 and 
about three miles east of the village of the same name. 

The half dozen ranges encountered were traversed by low passes 



Across Papagueria, 




Across Papagiieria. 5 

of easy grade, and in the approaches a few wells have been digged 
and walled by the Government, but as they are not suitably guarded 
or cleaned it is quite as well for the comfort of the traveller that 
their depth prevents a view of the water and its contents, which 
often smell vilely when brought to the surface. In one, the badly 
disintegrated remains of rattlesnakes and other animals were found, 
and all of the water on this portion of the route except that within 
25 miles of Tucson, was bad and perhaps dangerous, although no 
ill effects were experienced by any member of our party. 

The Oasis of Sonoyta. 

The general structure of the oasis of Sonoyta is fairly representa- 
tive of such formations in American deserts, and its principal fea- 
tures merit description. A great ovoid plain, forty or fifty miles 
across, lies mostly south of the International Boundary, with its 
narrower and low'er portion to the westward. The plain, once a^ 
basin-like valley, is now filled with detritus from the encircling moun- 
tains to a depth of a few hundred feet. The greater part of the 
precipitation here and on the slopes of the neighbouring moun- 
tains sinks down in this broken material, forming running streams 
on the surface only during seasons of heaviest precipitation. The 
water percolating through the detrital mass gradually makes its 
way toward the lowest part of the original valley, this being facili- 
tated, perhaps, by layers of clayey material or hard-pan impervious 
to water, with the result that in following these gently inclined 
strata it is brought to the surface by various converging lines of 
drainage at the lowest part of the gravel-filled valley within a mile 
of the International Boundary. The stream formed flows along 
over the margin of the clayey layer, being exposed to enormous evap- 
oration, and furnishing a surface supply which may be led out in 
conduits for irrigation purposes. Further down it encounters the 
sand or gravel beneath the clay and again sinks into the ground. 
In the brief seasons of flood the stream may run far down before it 
is swallowed by the porous sands, and as aridity increases the end 
of the water recedes far upstream. It is this short reach of living 
stream that forms the heart of the oasis, nourishing, as it does, a 
vegetation widely different from that of the surrounding desert and 
affording conditions for the cultivation of food-plants for the human 
animal. The oasis of Sonoyta has, doubtless, been the site of a 
cluster of habitations since the beginning of agriculture, and has been 
known to the Papagos for a thousand years by this name, meaning 
the place where corn (sonot) will grow. Very naturally, the upper 



6 



Across Papagueria. 



part of the oasis has the surest supply of water, and the steady popu- 
lation of about 150 people have shifted about in accordance with the 
changes in the stream and alterations in the irrigation systems. The 
lower, uncertain part of the stream, with its precarious conditions, 
has been the scene of hunter's camps and sporadic ventures with 
small flocks, the oft-recurring seasons of extreme drought discourag- 
ing any more serious operations. 

Thus the records show that in the early nineties, the entire popu- 
lation was centered about the Hacienda Santo Domingo midway of 
the oasis, but at the time of our visit the village of Sonoyta, at the 




Fig. 2. — buNOViA kivek, near the village 



head of the living water, was the centre of activity, the Mexicans, 
perhaps 75 in all, being accommodated here in characteristic adobe 
dwellings, while smaller clusters of wattled houses of the Papagos 
were scattered along the valley and down the stream for five or six 
miles. The Mexican alcalde and the "Jacke" (pronounced "Hacke") 
or "gobernador" of the Papagos being the only recognized officials 
and administrators of civil law. 

The old Hacienda of Santo Domingo, with its desiccated groves of 
fruit trees and grapes, ruined buildings and dismantled arrastra, 
presented a melancholy picture, although it was well understood 



Across Papagiieria. 7 

that the diversion of the waters of the oasis down to this point would 
practically restore it in a single season. 

In the lower part of the oasis the streamway bends to the north- 
ward to within a short distance of the International Boundary, and 
near here, at Ouitovaquita, a group of small springs ooze from the 
hillside a few feet north of the boundary line, and in flowing down 
to the lower ground their waters serve to irrigate a small field on the 
Mexican side. A single American had sought this refuge for the 
sake of the produce of the small field and of the small flock of goats 
which he tended. 

The ancient road from Sonora coming through Altar and Caborca 
led through the oasis of Sonoyta and across the desert to Altar, Cali- 
fornia, crossing the Colorado River at Yuma. In the earlier days 
it was much traversed by Spanish priests and the guards for the 
missions, this route having been followed by Father Kino as early 
as 1699, and soon became known as a "Camino Real." Later, 
especially during the rush to California consequent upon the dis- 
covery of gold, it was attempted by many inexperienced in the 
rigours of desert travel, and the long arid stretches between Sonoyta 
and Yuma became the scene of scores of tragedies, as evinced by 
the numerous crosses of stones which are thickly strewn along the 
way, especially in the vicinity of the Tinajas Altas, a series of kettle 
holes high up on the granite, containing the only supply of water in 
a three-days' journey. Naturally enough, the way became known 
as the "Camino del Diablo." 

Within a few minutes after our arrival in Sonoyta we learned 
that a party of six Japanese had come up through Altar and Caborca 
and had evaded the immigration guard at the oasis, going out over 
the old desert highway across the border to gain the freedom of the 
United States. Disaster was quickly encountered, and two of the 
party returned for water and help which was freely given by the 
natives. Again they made the trial, passing our camp by a detour 
in the night. A day later we encountered one on the desert, worn 
and exhausted, who intimated by signs that he and a companion had 
become separated from the remainder of the party and that his friend 
lay ill in a distant copse along the streamway of the Sonoyta. Sup- 
plies were furnished him and upon our return a few weeks later 
these two had made back to Sonoyta to recuperate from their strug- 
gle, while the fate of the remaining four remains unknown. The 
tangents are long from water hole to water hole and their end might 
remain undiscovered for a decade, although one would preferably 
hope that such endurance and determination might win a refuge. 



8 Across Papagueria. 

Barley, wheat, corn, melons, figs, beans, and grapes are grown by 
the holders of water privileges in the oasis, but in quantities barely 
sufficient for the needs of the inhabitants. Some foodstuffs, includ- 
ing sugar and grain, are brought in from the outside. The small 
fields with their crops of introduced plants formed a striking con- 
trast with the native vegetation fringing the streamway and the 
xerophytic forms of the adjoining desert. A heavy growth of mes- 
quite (Prosopis velutina) occurs in places, the arrow-weed "cochin- 
ilia" (Pluchea sericea) inhabits plots of alluvium in the bottoms, 
while the batamote (Baccharis glutinosa) is taken by the Mexicans 
to denote places at which good water may be obtained by digging. 
The oasis is remarkable in the fact that it furnishes conditions which 
bring together three species of Parkinsonia {P. aculeata, P. micro- 
phylla and P. torreyana). An elder tree (Sambucus glauca) is 
represented by some large specimens. Acacia greggii is abundant, 
while the spiny smoke tree, or indigo tree (Parosela spinosa), occurs 
in the lower part of the oasis growing out in the gravelly flats in 
streamways, as it does in the Salton basin. A willow and a poplar 
are comprised in the larger growths of the oasis. 

For a long period of years the oasis has practically been a free 
zone into which the products of Mexico and United States have been 
admitted, except for occasional application of customs regulations 
by visiting customs officials of Mexico. Official sanction for taking 
our large amount of equipment across the frontier into and out of 
the oasis into the country to the southward at this point was not 
easily brought about, however, and some intervention by President 
■Roosevelt and Secretary Root was necessary to secure arrangements 
by which we were given the desired permission. This entailed the 
presence of a Mexican customs official, and Teniente Jesus Medina, 
with a detail of four privates from the Guardia Fiscal, marched from 
La Osa, a hundred miles to the eastward, to vise our papers and re- 
ceive us into Mexico. This service was tactfully carried out, and, 
by engagement. Lieutenant Medina returned to Sonoyta two weeks 
later to render any aid necessary to the return of the expedition 
across the boundary, and give us full clearance. 

During our stay of two days at Sonoyta some progress was made 
in the geographical work of the expedition. Southward from the 
oasis lies the Cobabi Range, the culminating peak of which has been, 
and is still given on the U. S. hydrographic charts as 9,457 feet. A 
visit to the summit was made by Mr. Godfrey Sykes, who made the 
height as 4,325 feet, and, as the aneroid carried was tested before and 
after the ascent, this elevation is probably very nearly correct. 



Across Papagueria. 9 

From Sonoyta to Pinacate. 

Recruiting the expedition to a strength of nine men and seventeen 
horses, a start was made down the Sonoyta Valley on November 
loth, being stopped by the Sonoyta itself, which rose in flood as a 
result of rains in the Cobabi and Cipriano mountains, and subsided 
so quickly that it had only the volume of a streamlet on the following 
morning. We were now following the old Camino Real or "Camino 
del Diablo," a route which has been traversed by survey parties of 
the boundary commissions and other expeditions. The flood water 
had carried the stream a dozen miles below Agua Dulce, where a 




Fig. 3. — SINK OF the sonoyta river below aguadulce. 



stop was made before starting to negotiate the long, waterless stretch 
westward to the Tule Desert. Upon our return the stream was 
found to sink three miles below at the Salada, which is over a mile 
in length and includes the low alluvial flats bordering the stream- 
way. 

Here, as in similar spots in this region, were found growing 
patches of salt grass (Distichlis spicata), salt bush (Atriplex) , mes- 
quite (Prosopis), and many plants of Wisli^enia with bright yellow 
flowers. 

Our Mexican scout explained that water reappeared at a place 



10 Across Papagueria. 

lower down the courses of the river, at a place known as the "Bata- 
motal" (the place where the batamote, Baccharis, grows), at which 
place it is much less highly charged than here, and is drinkable. 

At this and other camps in the arid southwest, many opportunities 
have been found to make observations on the ends of the currents of 
desert streams in sinks and playas. The lessened evaporation gives 
the attenuated current greater volume during the night, and an in- 
crease is visible within an hour before sunset, while by morning small 
streams coming out of mountain caiions will be seen to make ovit a 
distance of a hundred yards farther than in the daytime, before sink- 
ing in the sand. 

While the wagons were being taken along the Camino del Diablo 
to the Tule Desert, a number of the party made a detour to the south- 
ward to examine a huge cinder cone, with a large and perfect central 
crater, known as the Cerro Colorado, that lies 12 miles east from 
Pinacate. Around its northern base is a great undrained area or 
playa, which accumulates considerable water in times of precipita- 
tion and bears a heavy crop of Indian wheat {Plantago aristata), 
upon which antelope were feeding. The base of the Cerro Colorado 
is fringed with a wide sloping zone of ash and fine cinder, suggestive 
of comparatively recent activity. 

A temporary supply of water, which had vanished a fortnight 
later, was found in depressions in other playas near Monument 180 
on our advance trip, and from a camp here the route was laid to the 
southward to gain the western slopes of the Pinacate Mountains 
proper. 

Progress now became somewhat more difficult. Slopes of rough 
lava and great stretches of malpais were interspersed with ridges and 
ranges of granite of varying height. Among these a route was found 
to within a mile of one of the largest outlying sunken craters of 
the group. Numerous flattish dunes and drifts of sand were also 
encountered. South of Monument 180, a distance of about 20 miles, 
a level pass was found leading directly in to the volcanoes. To the 
right" or westward of the pass were the irregular slopes and jagged 
summits of a small granite range, which rose abruptly from the plain 
on all sides and which we named the Hornaday Range, in recog- 
nition of the work of Dr. W. T. Hornaday, who travelled completely 
around them in company with the author and made an examination 
of the fauna. 

The Pinacate volcanoes might be enclosed in an oval figure, 60 
miles in length and half that width, with its long axis running from 
southeast to northwest, lying directly inland from Adair Bay, from 



Across Papagueria. 



11 




12 Across Papagueria. 

which the cuhninating peak is about 32 miles distant. The ascent 
of the main peak was made on November 20 by five members of the 
party and a record left in a cairn on the summit. A count made of 
the cones and craters within a limited section of the region which 
could be seen clearly on the hazy day on which the ascent was made 
justifies the estimate that at least 500 cones and craters in various 
states of preservation were included in the Pinacate volcanoes. Pina- 
cate reaches an elevation of 4,060 feet, and the summit represents 
the eastern half of one of the largest craters, while around it in all 
directions lie other cinder cones, the slopes of which have the maxi- 




-PAl'AGO TANKS IN PINACATE MOUNTAINS. 



mum steepness permitted by the character of the cinder of which 
they are composed. Work on these slopes was accomplished with no 
little difficulty. In addition to the laboured climbing in the sliding 
ash, this material afforded suitable conditions for Opuntia higelovii, 
and the climber might by a slight slip find himself precipitated" into a 
clump of it, with consequent discomfort or even serious danger. 

The secondary peak of the range, also a fragment of a huge crater, 
lying to the southeast of the main cone and but slightly less in eleva- 
tion, was designated as Carnegie Peak by the members of the expe- 
dition. (See map 2.) 



Across Papagueria. 13 

On November 14th, the expedition traversed an extensive plain 
made up of the gentle detrital slopes from encompassing granite 
ridges, worn down nearly to base level and bearing great stretches of 
galleta grass and creosote bush, over which roamed numbers of wild 
horses. The close of this day's journey found us camped in Mac- 
Dougal Pass, which separates the Hornaday Mountains from the 
main volcanic formations of the Pinacate volcanoes to the south- 
eastward. On the following day the resumption of the march 
brought us within three miles of a field of lava impassable with 
vehicles, but within easy reach of some of the more interesting topo- 
graphical features of the region. Here the wagons were unpacked, 
the equipment assorted, and a selection necessary for further work 
was carried in on pack saddles to the Papago tanks. These tanks 
are a series of kettle holes in the granite, laid bare by erosion of a 
streamway carrying the drainage of enclosed valleys in the northern 
part of the Pinacate volcanoes. The tanks contained a few thousand 
gallons of water in the aggregate and are probably never totally 
emptied, though the level of the water was perceptibly lowered by the 
draft made on them during the fortnight of our occupation. These 
tanks are the most reliable source of water in the northern section 
of the volcanoes, and after they are passed the explorer must pro- 
ceed to the southern end of the range to the Cuervas tanks, or to the 
Chives tanks, although we found a plentiful supply in the Tule tanks, 
18 miles to the southward. 

Abundant indications of former occupation by Indians, probably 
of Piman stock, are found. Near all of the water holes are num- 
erous mealing holes, which by their depth testify to long usage, while 
converging trails are plainly marked in the lava and granite, those 
coming into the Papago tanks being worn to a depth of over a foot 
in places. A second convergence is to be noted of ancient highways 
which lead to the salt deposits on the shore of the Gulf, near the 
northern end of Adair Bay. The region of the volcanoes around 
the water holes and including the salt beds appears to have been most 
recently occupied by a section of the Papagos known as the Areneros, 
who seem to have been much more devoted to hunting than their 
agricultural relatives to the eastward and northward, and whose 
aggressive qualities led them into much trouble with their Mexican 
neighbours and Indian relatives. The entire region has been evacu- 
ated by them, however, and, except for an occasional pilgrimage to 
the salt beds, the water holes are entirely unoccupied. 



14 Across Papagiieria. 

Craters of Pinacate Volcanoes. 

The northwestern part of the Pinacate region which we had 
entered is characterized by great sunken craters, the rims of which 
He but httle above the level of the surrounding lava slopes of older 
formation. Three of these were examined with some care. One 
of the largest lies almost due south from the pass at the east end of 
Hornaday Mountains, and has a diameter of about 1,200 yards at 
the bottom, with almost vertical walls going down 400 feet. So far 
as our examination could be depended upon to yield an accurate 
interpretation, this crater had thrown out cinder and mud at various 
times, as evinced by the deposits on the plain around its rim. The 
walls showed granite strata and various lava deposits from older 
volcanoes. The rim had been eroded down at a few places and the 
detritus carried by small streamways toward the centrum of the 
floor. The larger and more striking plants had arisen along these 
small streamways, thus having the appearance of radiating from the 
central portion toward the rim. Among these were the sahuaro, 



% ^^,^ 



^'^ " III; ,„„,„ „,,„,„,,,,, 




Profile i. — macdougal crater, 400 feet in depth. 

ocotillo, galleta grass, dodder, Parkinsonia, ajo. Hibiscus, Trihulus, 
Pedis, golondrina {Euphorbia) , Dalea and Amarantus. The soil in 
the extreme lowest part of the crater was distinctly moister, and 
here the herbaceous forms mentioned grew very densely, making a 
distinct patch that forms a marked feature when viewed from the 
rim. 

The Molina crater, which lies two miles to the eastward, likewise 
has its rim but little above the surrounding lava beds, its name being 
suggested by its form, being, in fact, composed of three craters, the 
intervening walls having been carried away to give the aggregate a 
trifoliate form. 

Sykes crater, 3 miles north of Papago tanks, has built up a rim 
on the stratified material through which it penetrates, so that it has 
a depth of 750 feet. The walls are so little broken that in only one 
place has a slide been formed, down which a descent may be made. 
Mr. G. Sykes made the descent and obtained the measurements and 
material described and his name has been applied to the crater. 
Encelia, Sphaeralcea, Nicotiana, mesquite, Baccharis, palo verde. 



Across Papagiieria. 15 

Covillca, sahuaro, galleta grass and Bigelow's opuntia were found on 
the rough floor of the crater, the bowl of which has a diameter less 
than twice its depth, and hence presents the most imposing appear- 
ance of any that were visited. Here, also, the product of eruptions 
included both cinders and mud of comparatively recent date. 

To the westward of Sykes crater lies Phillip's Butte, which rises 
directly from the crater with which its slopes are continuous and 
reaches an elevation of about 1,500 feet. 

In order to make the ascent of Pinacate and visit the shore of the 
Gulf, five members of the party left the main camp at Papago tanks 
and proceeded with a pack outfit to Tule tanks, 18 miles to the south- 
ward. Bands of antelope were encountered on the intervening slopes, 
while the entire region contains numbers of bands of mountain sheep 




Fig. 5. — SYKES cratek in pinacate mountains. 

{Ovis canadensis) . The sahuaro, Covillca and an Ephedra, as well 
as a prickly pear, are found near the summit of Pinacate and col- 
lections were also made, including Eriogonmn, Perityle, Monardella, 
Verbena, Sympetala rupestris, Groton, Euphorbia, and a few others, 
the identity of which is not yet known. Mr. G. Sykes marched from 
the camp at Tule tanks to the shore of the Gulf and returned, a total 
distance of 42 miles, in one day, extending the line of our inspection 
to sea-level, and allowing, opportunity for the correction of aneroids. 
The shore near Adair Bay is fringed with wide flats nearly bare, 
which are partially submerged at the highest tides. Above this 
is a belt 3 to 5 miles in width, in places covered with a dense growth 
of galleta grass, beyond which lie the great ranges of sand dunes, 
piled up to a height of 80 to 100 feet in places, making a zone 
several miles wide. The streamways from the slopes come directly 



16 Across Papagueria. 

against the upper side of these dunes and repeated floods have car- 
ried down material which has been spread out to make broad playas 
at these places. Such a termination is reported of the Sonoyta River, 
although not actually observed by any member of our party. This 
river during the season of greatest floods makes to the eastward and 





500 looo 1500 feet. 

Profile 2.— sykes crater, 750 feet in depth. 

in a southerly direction past the Pinacate volcanoes, and then veers 
slightly to the westward, coming against the dunes south of the main 
peak, and sharing the fate of the lesser streams. Previous visitors 
to contiguous regions have described the Sonoyta as going around 
the north end of the range, a statement now corrected for the first 
time. 

Features of the Vegetation. 

The region traversed by the expedition might be properly termed 
the northernmost portion of the desert which extends southward 
along the Pacific coast to the Isthmus of Tehuantepec. The precipi- 
tation is less than a dozen inches, except on the higher summits, the 
greater part of the yearly rainfall coming in midwinter and mid- 
summer. Temperatures of ii8° and 120° F. have been recorded in 
the lower levels, some places showing a daily maximum during por- 
tions of six months of every year. The possible evaporation that 
would ensue from a water surface on the plains would probably be 
between 70 and 80 inches per year, or about six to eight times the 
precipitation. The general aspect of the vegetation is highly xero- 
phytic, although of some abundance. An analysis of the flora, how- 
ever, shows that a large proportion of it, as in all western American 
deserts, is made up of annuals and perennials which are active only 
during the periods of maximum precipitation in summer and winter. 
These forms do not exhibit any structures which distinguish them 
from mesophytic species of moister regions, but they have peculiar 
rhythms and dormancies. The seeds of many of the winter annuals 
will germinate only in the low temperatures of the winter months, 
lying wholly inactive during the summer rains, while the summer 
annuals are equally unafifected by the moisture and stimulus of change 



Across Papagncria. 17' 

of the cooler months. As a result of the arrangements in question, 
the vegetation shows an intricate interlocking of temperate and sub- 
tropical forms with, of course, a very large number of endemic 
species of both classes. Legumes are abundant and are represented 
by a great number of forms. Most remarkable of all, however, are 
the cacti, a group of comparatively modern origin, and including 
hundreds of species, some of which are extremely restricted in dis- 
tribution. 

Of these, the sahuaro, or giant cactus (Cereus giganteus) is prob- 
ably the most prominent by usefulness and obtrusiveness of all the 
striking forms that inhabit the desert land of the Papagos. It ranges 
from the Tonto basin in central Arizona westward to the Colorado 
River, which it crosses to occupy a small area in California in the 
vicinity of the mouth of the Bill Williams River. It extends to the 
eastward to the drainage of the San Pedro River and southward in 
Sonora to the latitude of Guaymas, its exact southern limit not being 
determined, and follows close to the Gulf up to its head. In the 
northern portion of its range it occupies sunny slopes at an elevation 
of 4,000 feet and it descends into some of the old craters of the Pina- 
cate volcanoes to a point but little above the sea-level, climbing the 
main peak near by to the maximum elevation. As the limits of the 
range of the sahuaro are approached, branching becomes less pro- 
fuse and the outlying individuals show simply columnar trunks, usu- 
ally showing some marks of the stress under which they exist. In 
more favourable localities an unending variety of grotesquely ar- 
ranged branches is to be seen and secondary branches are exhibited 
in some instances. Native guides are given to informing travellers, 
with apparent sincerity, that the branches are in reality separate 
plants which have risen from seeds deposited in cracks of the trunk 
by woodpeckers and other birds. It has been pointed out recently 
(Turrell, C. A., Univ. of Ark. Monthly, Jan., 1908) that the name 
for the great tree cactus {Cereus giganteus) must have been a Cas- 
tilian rendering of an ancient name in use when the Spanish explor- 
ers first came, and as the use of the g with the sound of zv was un- 
known, the proper spelling of the name of this plant would be 
"sahuaro" instead of "saguaro." 

It would be difficult to estimate exactly the importance of this 
plant to the animal life of the area which it inhabits. Its flowers, 
opening in May and June, offer food and shelter to countless swarms 
of small bees and gnats. The ripening fruits furnish a profusion of 
seeds and a wealth of sweetish pulp to birds and smaller mammals, 
while the Indian makes use of both portions of the fruit, fresh, fer- 



18 Across Papagueria. 

merited and preserved. Scores of tribal battles have been fought in 
Papagueria over the sahuaro harvest' The seeds which reach the 
ground quickly germinate in the baking soil, and the tiny capsules of 
acid water stored in the plump spineless hypocotyl constitute a most 
attractive morsel for thirsty and hungry animals, and not one seed- 
ling in a million survives the first year, in consequence. The bases 
of large plants are stripped and gnawed by rabbits and hares in the 
southern portion of the habitat, while carpentarios, or woodpeckers, 
bore huge cavities into the soft outer tissue which are quickly lined 
with a callus formation, forming a fine nesting cavity. These cavi- 
ties also offer storage room and shelter for swarms of honey bees. 
With so many animals making use of the fleshy trunk and branches, 
the greater number of the sahuaros perish before reaching a height 
of forty feet. The central pith and the thick outer cylinder of pulp 
quickly decay, leaving a fascicle of woody rods anastomosing in the 
older lower portions, but free in the upper terminal parts. 

The woody skeletons of the sahuaro form a light and strong build- 
ing material much used by the Papagos in making the picketed walls 
of their jacales, or barriers around small gardens or corrals. Illus- 
trations of such uses are to be seen in the city of Tucson. Recently, 
Mr. Fred. C. Wright has discovered a process of dehydration and 
tanning that will greatly increase the usefulness of the sahuaro. 
(Plant World, May, 1908.) 

The opuntias, with flattened stems as well as the cylindrical forms, 
force themselves persistently on the attention of the traveller in 
Papagueria, and great discomfort or even serious injury may result 
from an unguarded encounter with these armed plants. The heavy 
rigid spines. may penetrate deeply into the flesh, and the glochids, 
which form short tufts at numerous places on the surface and are 
easily detached, quickly work into the skin with highly unpleasant 
results. It is to these structures that attention is chiefly directed in 
the effort to get an opuntia useful for forage and salad. A dozen 
species spineless, or nearly so, are known ; but the breeder must get 
a form which does not develop the glochids beyond a rudimentary 
stage, if the most offensive features of the armament are to be 
avoided. 

Some of the cylindrical forms are arborescent, with widely spread- 
ing branches. The joints are easily detachable, so that a slight con- 
tact causes the spines to pierce the clothing or skin and a joint of the 
stem comes away bristling with a score of spines and some of these 
also pierce the flesh. The instructed use a stick or a pair of tweezers 
to remove the pest. Dogs, horses and cattle reared in cactus regions, 



Across Papagueria. 19 

learn to free themselves by a shaking motion. Attempts to remove 
the detached joints by the fingers are often disastrous. 

The ease with which the joints are detached, the facility with 
which they become attached to animals and the rapidity with which 
these segments root and form new plants when dropped, make this 
one of the most important methods of reproduction. This is true 
especially of Opuntia mamillata and 0. fulgida. 

These two forms were formerly thought to be included in a single 
species, but on all of the expeditions from the Desert Laboratory 
they have been found easily distinguishable. They offer a marked 
example of closely allied forms living in the most intimate proximity. 

The acid fruits are not set free until they are three years old or 
even more, in some instances. After the pulp decays, the hard seeds 
lie on the ground inactive for months or even years, meantime being 
subject to the action of numerous rodents which gnaw through the 
hard outer coat to get at the embryo. Both species are known as 
"cholla," a name loosely used, and sometimes applied to any cylindri- 
cal opuntia, although it strictly belongs to a species native to Baja 
California {Opuntia cholla) . 

A number of rodents fortify their burrows with joints of the cholla 
which are dragged into such position around the entrances as to 
allow a crooked passage for the occupants, but which would dis- 
courage the marauding coyote, cat or fox. 

The spines and glochids of the cacti do undoubtedly lessen the 
ravages of grazing animals to some extent, but no ground is afforded 
for the conclusion that the armature is a direct and purposeful re- 
sponse to the injuries inflicted by animals. The structures in ques- 
tion seem to have been induced by aridity and in a dozen species the 
evolutionary development has been carried still farther and the spines 
are reduced to the merest rudiments. Singularly enough, the two 
poorly armed species, occur^ng in the vicinity of Tucson, are not 
seriously molested by animals. It is also to be noted that while the 
cacti seem to be especially suited for arid conditions, yet many species 
occur in moist tropical forests. 

Two massive forms of melon cacti or biznagas {Echinocactiis 
ivislizcni and E. emoryi) were encountered by our expedition at 
elevations above a thousand feet in Sonora and Arizona, while a third, 
with a number of smaller heads in a cluster, was seen nearer the Gulf 
of California. The larger species often measure over 5 feet in 
height, with a diameter of more than 2 feet at the base, containing 
as much as 6 or 8 gallons of water. This sap is only slightly charged 
with substances ordinarily in solution in the plant-cell, and an Indian 



20 Across Papagueria. 

runner, striving to make a swift journey in Papagueria, need not 
carry water with him, but may resourcefully shape his way to meet 
these "biznagas," from which a grateful supply of satisfying liquid 
can be quickly obtained. Some travellers speak slightingly of the 
juice as a drink, and magnify the difficulty of its extraction. It has, 
however, proved useful on many expeditions, and if the thirsty travel- 
ler is so fortunate as to be armed with an ax or a large knife, he may 
secure a quart of liquid within seven to ten minutes. Lacking these, 
he must burn away the huge spines and then crush the top and pulp 
with a stone before the juice can be squeezed with fingers into a cen- 
trally made cavity, a method which may need twice as much time, 
but which might avoid serious consequences from thirst in a region 
in which a man at work uses as much as sixteen pints of water daily. 

Not all melon cacti can be expected to yield their store of water 
so readily, however. Echinocactus grandis attains the height of 
seven or eight feet and a thickness of a yard in the desert of Tehua- 
can in southern Mexico. The firm pulp is heavily loaded with lime, 
so that when chewed it is unpleasantly gritty; the juice is not obtain- 
able by the methods used with the Sonoran species. It is reported, 
however, that water is obtained from some species in South America 
by the native Indians. 

A general view of the entire region shows that it includes as the 
principal topographical features a series of minor ranges of moun- 
tains trending in a northerly and southerly direction, w^hich have 
undergone tremendous erosion in a desert climate, with the result 
that the intervening areas are great valleys or bolsons filled with 
detrital material brought down from the mountains. The soil is 
very poor in humus, the drainage is undeveloped, oases of peculiar 
structure occur, the diurnal changes of temperature are of wide 
amplitude, the etit'ects of wind erosion are very marked, the precipi- 
tation sustains a very low ratio to the possible evaporation, as a con- 
sequence of which all areas under 4,000 to 6,000 feet are strongly 
desert in character. Within the limited areas offered by the higher 
mountain slopes, much more mesophytic conditions prevail by reason 
of the greater precipitation and decreased evaporation. In such 
comparatively humid localities a vegetation of mesophytic forms is 
encountered, forming islands in this great desert. Also at lower 
levels there occur a large number of species which carry out their 
entire cycle of activity during the brief rainy seasons or periods of 
greatest precipitation, and these do not exhibit any marked xero- 
philous qualities, except that the dormant seeds or quiescent roots 
are capable of withstanding great periods of drought without damage. 



Across Papagueria. 21 

The greater proportion of the area, however, is occupied by true 
desert species, which by structure and physiological capacity are well 
equipped for the arid conditions prevalent. In some, structures 
which prevent loss of water are most noticeable, while in others, the 
capacity for the absorption and retention of surplus water during 
times of precipitation is developed to an enormous degree. 

So far as the geological record is to be taken as fairly interpreted, 
arid conditions have prevailed here since Pleistocene times. No 
unmistakably xerophilous plant remains have yet been unearthed by 
the palaeontologist, and we are driven to the conclusion that the cacti 
and other characteristic plants of this region must have originated 
within the present arid period. 

The overshadowing influence of desiccation on development makes 
it impossible to select any given place as a meeting or mingling 
point of the forms occurring at the higher level and those native to 
the coastal region and extending far to the southward. 

A number of species are found over its entire breadth from ele- 
vations of 3,000 and 4,000 feet in southeastern Arizona to the dunes 
near the shore of the Gulf, a distance of 200 miles. Among these 
are to be included Cereus giganteus, Covillea tridentata, Encelia fari- 
nosa, Prosopis velutina, Fouquieria splendens and Parkinsonia micro- 
phylla, all of which are essentialy desert species, showing marked 
xerophytic structures. Some of these species extend hundreds of 
miles north and south of the region under discussion, with a total 
range in excess of the variation of conditions which would be fur- 
nished by a vertical mile of mountain slopes. Then a large number 
of other forms occur in very narrowly restricted areas or pockets, 
evidently determined by local drainage or moisture conditions, so 
that an analysis of their inter-relations which would make possible 
a delimitation of "life zones" is extremely difficult. Thus, in trav- 
ersing the slopes from 4,000 feet in the vicinity of Tucson to sea- 
level, the only place where any distinct alteration in the character of 
the flora may be discerned is at the junction of the lava beds with 
the gravelly detrital plains, and at the contact of the sand dunes with 
the playas on one hand, and at the contact of the sand dunes with 
the Gulf. 



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